A method is disclosed herein for imaging at least one autonomic nervous system synaptic center in a subject, as well as a method of diagnosing and/or monitoring a medical condition or disease associated with an autonomic nervous system, and a method of guiding a therapy of such a medical condition or disease. The methods comprise administering to the subject a radioactive tracer which selectively binds to autonomic nervous system synapses; measuring radioactive emission of the tracer to obtain data describing a distribution of the tracer in the body; and analyzing the data in order to identify at least one region exhibiting a high concentration of the tracer. Further disclosed herein are radioactive tracers, uses thereof, and an apparatus, for use in a method disclosed herein.